<div id="consent">
  <p>
    This is a demo experiment, with this minimal consent form being loaded
    as an external html document. To continue, click the checkbox below
    and hit "Start Experiment".
  </p>
  <p>
    <input type="checkbox" id="consent_checkbox" />
    I agree to take part in this study.
  </p>
  <button type="button" id="start">Start Experiment</button>
</div>
